1. Field of the Invention
The present invention relates to a three-dimensional distance measurement apparatus, a three-dimensional distance measurement method, and a non-transitory computer-readable storage medium.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2008-276743 discloses a three-dimensional distance measurement method in which the spatial resolution of a projection pattern for distance measurement points is different for each region in measuring the three-dimensional distance using pattern projection.
In the three-dimensional distance measurement method described in Japanese Patent Laid-Open No. 2008-276743, distance patterns between measurement lines in a projection pattern having measurement lines (distance measurement points) embedded with identification information may have two distances.
Thomas P. Koninckx, Andreas Griesser and Luc Van Gool, “Real-time Range Scanning of Deformable Surfaces by Adaptively Coded Structured Light”, 3DIM 2003. Proceedings. Fourth International Conference, 293-300 discloses a three-dimensional distance measurement method using different feature patterns of reference lines. V. Lepetit and P. Fua, “Keypoint recognition using randomized trees”, IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 28, no. 9, 2006 discloses a position and orientation measurement method using image features such as edges and feature points detected on a two-dimensional image. D. G. Lowe, “Fitting parameterized three-dimensional models to images”, IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 13, no. 5, pp. 441-450, 1991 discloses a method of recognizing the position and orientation of a measurement object by performing model fitting to a two-dimensional image using model information stored in advance. Furthermore, Seiji Iguchi and Kosuke Sato, “Three-Dimensional Image Measurement” (Shokodo, 1990) discloses a method of calculating the three-dimensional distance information of a measurement object by projecting a plurality of projection patterns each embedded with code information on the measurement object and decoding the code information of a plurality of captured images.
In a conventional three-dimensional distance measurement method, since the spatial resolution patterns of measurement lines are limited to two types and to a direction perpendicular to the measurement lines, it is impossible to set the spatial resolution of distance measurement points for each arbitrary region. Furthermore, when parallel processing is executed by dividing a distance measurement region into a plurality of local regions, uniforming arithmetic processing amounts for respective local regions according to the spatial resolution of distance measurement points is not considered, thereby decreasing the effect of shortening the processing time by the parallel processing.
The present invention has been made in consideration of the above problems, and has as its object to set the spatial resolution of three-dimensional distance information for each local region, thereby executing efficient parallel processing.